Spect Motion-Correction

1. A method of generating motion-corrected images comprising: acquiring a plurality of acquired projections of a subject in an examination region at each of a plurality of angular orientations; reconstructing and image degrading factor correcting the acquired projections into a motion-artifacted, image degrading factor corrected image; forward-projecting and image degrading factor modeling the motion-artifacted, image degrading factor corrected image along each of a plurality of projection directions corresponding to the angular orientations of the measured projections to generate a plurality of image degrading factor modeled forward-projections; comparing the acquired projections and the image degrading factor modeled forward-projections corresponding to the same angular orientation to generate a patient motion correction vector; applying the patient motion correction vector to the acquired projections to form motion-corrected projections in a common motion state; reconstructing and image degrading factor correcting the motion-corrected acquired projections into a motion-corrected, image degrading factor corrected image.

2. The method according to claim 1 , wherein the image degrading factor correcting is integrated with the reconstructing steps.

3. The method according to claim 1 , wherein the image degrading factor correcting includes attenuation correcting and includes: using a 3D attenuation map of the subject in the examination region to perform the attenuation correcting.

4. The method according to claim 1 , wherein the image degrading factor correcting step includes at least one of: compensating for radioisotope decay; recovering resolution; compensating for scatter; and compensating non-ideal imaging system behavior.

5. The method according to claim 1 , wherein image degrading factor correcting includes: convolving a 3D scatter kernel with an attenuation map; during each reconstructing step, operating on the acquired and motion corrected projections with the result of convolving 3D scatter kernel and attenuation map.

6. The method according to claim 1 , further including: forward-projecting the motion-corrected image to generate motion-corrected forward-projections; motion-correcting the acquired projections; comparing each of the motion-corrected forward-projections with the motion-corrected acquired projection along the corresponding angular orientation to refine the motion correction.

7. A non-transitory computer medium carrying software which controls one or more processors to perform the method according to claim 1 .

8. A processor programmed to perform the method according to claim 1 .

9. A system for generating motion-corrected nuclear images comprising: one or more processors programmed to perform the method according to claim 1 ; a display unit which displays at least a portion of the motion-corrected image.

10. A system for generating motion-corrected images comprising: a reconstruction processor or engine configured to reconstruct projections along each of a plurality of projection directions into a reconstructed image; at least one image degrading factor compensating processor or engine configured to compensate for image degrading factors, the at least one image degrading factor compensating processor or engine being included in the reconstruction processor or engine, such that the reconstructed image is image degrading factor compensated; an image memory configured to store the image degrading factor compensated reconstructed image; a motion correction processor or generator including: a forward-projector configured to forward-project the image degrading factor compensated reconstructed image from the image memory along the projection directions as a series of forward-projections, an image degrading factor modeling processor downstream from or integral with the forward-projector configured to model the forward-projections for the image degrading factors, a comparator configured to compare each forward-projection with one of the projections, wherein the forward-projection and the projection are in a common projection direction to generate a motion correction, a projection correction processor or generator configured to correct each of the projections with the motion correction to form motion-corrected projections; wherein the reconstruction processor or engine and the image degrading factor processor or engine are configured to reconstruct and image degrading factor compensate the motion-corrected projections into a motion-corrected image degrading factor compensated image configured to be stored in the image memory.

11. The system according to claim 10 , wherein the image degrading factors include resolution recovery, scatter correction, image noise reduction, compensation for non-ideal system behavior, and decay of radioactivity during data acquisition.

12. The system according to claim 10 , wherein the reconstruction processor includes the motion correction processor or generator such that the motion correction is modeled during the reconstruction of the projections.

13. The system according to claim 10 , wherein the reconstruction processor or engine and the motion correction processor or generator are configured to iteratively correct for motion to generate at least a first generation motion-corrected image degrading factor compensated image and a second motion-corrected image degrading factor compensated image.

14. The system according to claim 10 , wherein the image degrading factor modeling processor models the forward-projections to simulate the acquired scatter artifacted nuclear projections.

15. A system for generating motion corrected nuclear images, the system comprising: a projection memory configured to store acquired scatter artifacted nuclear projections; an image memory configured to store reconstructed images; one or more processors configured to: receive the acquired scatter artifacted nuclear projections from the projection memory, correct the acquired scatter artifacted nuclear projections with a motion model or vector to create scatter corrected nuclear projections, reconstruct the scatter corrected nuclear projections into a scatter corrected image, forward project and scatter model the scatter corrected image to generate scatter artifact modeled forward projections which simulate the acquired scatter artifacted nuclear projections, refine the motion model or vector based on a comparison of the generated scatter artifact modeled forward projection and the acquired scatter artifacted nuclear projections.